U.S. Pat. No. 3,888,750 discloses a process for decomposing water which involves the following electrolytic reactions: EQU SO.sub.2 +2H.sub.2 O.fwdarw.H.sub.2 SO.sub.4 +2H.sup.+ +2e.sup.-( 1) EQU 2H.sup.+ +2e.sup.- .fwdarw.H.sub.2 ( 2)
These reactions take place in an electrolytic cell, the first reaction occurring at the anode and the second reaction at the cathode.
One of the difficulties is making this process efficient has been finding an anode which would be stable in the concentrated sulfuric acid anolyte and which would require as little electrical energy as possible to oxidize the SO.sub.2 to sulfuric acid. Until now, the best anode that has been found is the carbon cloth supported electrode disclosed in U.S. patent application Ser. No. 269,135, filed July 1, 1981 by W. T. P. Lu and R. L. Ammon now U.S. Pat. No. 4,349,428. A suspension of platinum, palladium, or palladium oxide, carbon powder, and polytetrafluoroethylene was poured over a carbon cloth. A vacuum on the other side of the cloth removed the water forming a layer of solids on the cloth. The cloth was then compressed and sintered. While it is not mentioned in U.S. Pat. No. 4,349,428, the usual practice was to place a perforated platinum spacer over the top of the cloth to support it in the cell. The purpose of the perforated platinum spacer was to prevent the creeping of a catalyst layer into the grooves of the carbon current collector. While the sheet was necessary to hold the electrode in place, it was expensive and lowered the performance of the cell because it impeded the movement of hydronium ions.